To provide a simple and efficient system capable of integrally controlling to take measures for an occupied memory condition in a memory section and to retrieve image information by an index in terms of a low cost and small image forming apparatus, particularly one having a simple structure.

This image forming apparatus 10 comprises an operating section 21, a timer section 22 and a number generating section 24 as a management information generating means that generates management information by each image information in order to manage execution of retrieving, erasing, compressing and printing of the image information stored in a memory section 12. The image forming apparatus 10 further comprises an index generating section 23 for generating an index sheet indicative of a summery of the image information in the memory section 12. A control section 16 executes controlling in accordance with the management information and allows an image forming section 15 to print the index sheet on an as-needed basis.